Confocal and interferometric confocal microscopy has been used to measure lateral spatial properties of trenches and trench arrays (see S. S. C. Chim and G. S. Kino, “Optical pattern recognition measurements of trench arrays with submicrometer dimensions,” Applied Optics 33, pp 678–685, 1994). However, confocal and interferometric confocal microscopy has not thus far been used to obtain information about the depth and widths of trenches.